In the image forming apparatus using the electrophotographic type or the electrostatic recording type, a toner image formed on an image bearing member by an appropriate process has been transferred onto a toner image receiving material. Toner (transfer residual toner) remaining on the image bearing member after a transfer step is collected by being removed from on the image bearing member by a cleaning means. As the cleaning means, a cleaning device including a cleaning blade as a cleaning member provided in contact with the image bearing member and a cleaning container for supporting the cleaning blade has been used in many cases. This cleaning device scrapes off the transfer residual toner of the moving image bearing member and collects the toner in the cleaning container by the cleaning blade. The transfer residual toner collected in the cleaning container is fed to an outside of the cleaning container by a feeding screw as a feeding means provided in the cleaning container. The transfer residual toner discharged from the cleaning container is sent to a waste toner box.
In such a cleaning device, there is a problem that the toner is deposited and accumulated on a wall surface of the cleaning container around the feeding screw and it becomes difficult to discharge the toner to the outside of the cleaning container. Particularly, the toner after cleaning such that the toner is collected from the image bearing member after being subjected to an image forming process is poor in flowability and is liable to accumulate.
Against such a problem, in Japanese Laid-Open Patent Application Hei 7-168492, a constitution in which an electrode is in the neighborhood of a feeding screw and renders the toner difficult to deposit on a wall surface of a cleaning container by applying a voltage of an opposite polarity to the polarity of the toner to the electrode and thus accumulation of the toner is alleviated has been proposed.
Further, in Japanese Laid-Open Patent Application 2008-224726, as a constitution for loosening (collapsing) toner accumulated in the neighborhood of a feeding screw, a constitution for loosening the toner deposited on the feeding screw by a needle-like stirring member which repeats a rotational operation by rotation and a self-weight of the feeding screw has been proposed.
However, in the constitution of Japanese Laid-Open Patent Application Hei 7-168492, a cost is remarkably increased by providing the electrode. Further, a potential of the toner collected in a cleaning device is not necessarily either one polarity of positive or negative, but in general, the toner having both the polarities is collected even in a small amount. Even if deposition, onto the wall surface, of most toner charged to either of the positive or negative polarity can be suppressed, even in a small amount, the opposite-polarity toner is rather liable to deposit on the wall surface. It would be also considered that voltages of both polarities are applied to the electrode in an appropriate proportion in a switching manner, but it is difficult to control a proportion of polarities of potentials of the toner collected in the cleaning device, and therefore, it is difficult to set the proportion of the positive and negative polarities. Further, when such a constitution is employed, the cost further increases.
Further, in the constitution of Japanese Laid-Open Patent Application 2008-224726, the stirring member is rotationally operated so as to sink between pitches of the feeding screw by its own weight, but under only its own weight, it is difficult to cause the stirring member to perform a desired rotational operation while loosening the accumulated toner. Particularly, loosening of the toner accumulated on the wall surface of the cleaning container by applying the constitution of Patent Document 2 is difficult because it is difficult to set a self-weight direction of the stirring member at a screw direction so that the toner accumulated on the wall surface is sent toward a screw side.